In 1950, the first real-time, interactive computer was completed by a design team at MIT. The "Whirlwind Computer," as it was called, was a revamped U.S. Navy project for developing an aircraft simulator. The Whirlwind used a cathode ray tube and a light gun to provide interactivity. The Whirlwind was linked to a series of radars and could identify unfriendly aircraft and direct interceptor fighters to their projected locations. It was to be the prototype for a network of computers and radar sites (SAGE) acting as an important element of U.S. air defense for a quarter-century after 1958.
